Power steering pump

ABSTRACT

It is disclosed that a power steering pump. Which is characterized in that the front oil distributing plate is enclosed with front wall of the inner cavity of the pump body to form a front outlet cavity, a valve bore being formed at outer circumference side of the inner cavity of the pump body communicates with the front outlet cavity, a flow securing control valve is disposed within the valve bore, the front outlet cavity communicates with an oil outlet hole at the front portion of pump body through a high-pressure oil passage. The invention adopts a front high-pressure cavity configuration of the pump body to shorten the length of high-pressure oil passage, which hence avoids steering pump failure caused by aggressive overheating generated in the traditional configuration with excessive length of the flow passage and bending.

TECHNICAL FIELD

The present invention generally relates to a vehicle hydraulic power steering pump, in particular, the present invention relates to a vehicle hydraulic power steering pump that can reduce the temperature of vehicle steering system.

BACKGROUND

In recent years, as the rapid development of national economy, such as vehicle industry, the demand to large-tonnage vehicle with dual front axle structure for loading, mining or construction is increasing. The torque required by driving the front wheel for steering increases as loading capacity increased, which in turn requires increasing the diameter of steering cylinder bore, thereby increasing the flow rate of steering pump, meanwhile, the dual-front-axle vehicle attached with power cylinder also requires adding certain flow rate. The larger flow rate demands, the higher corresponding temperature of steering system increases. In view of various operating conditions of the current domestic vehicle, such as serious overloading, baneful road condition, or improper manner in customer's use and so on, high temperature is more prone to incur. As the components within the steering pump are still preciously processed, at a high temperature they will expand to increase the friction there between, and the steering system oil under the high temperature will go thin or metamorphism, which also affects the lifetime of steering system.

At present, the steering pump in prior art is to use a front cavity (nearby the drive gear) low-pressure configuration as seen in FIG. 1, which mainly consists of a pump body 3, a rear cover 19, a rear oil distributing plate 10, stator 12, rotor 13, blades 14, front oil distributing plate 15, positioning pin 11, a pump shaft 17, a bearing 2, a flow securing control valve installed within a valve bore of said pump body 3, valve seat 8, and a conical valve core 6, as well as a number of seals and springs. Wherein a high pressure oil passage B is disposed nearby the rear cover 19. FIG. 2 shows the configuration of internal high pressure oil passage 21 of said pump body 3 within the steering pump in detail (the portion displayed in dense section line), the configuration of said high pressure oil passage 21 is long and exists bending, generating the following defects like:

(1) three bores of said high pressure oil passage portion illustrated in FIG. 2 with medium density profile are required through processing which procedure is complex and increases the cost, moreover, the passage portion of non-smooth transition affects the smooth operation of high pressure oil; (2) Too long passage occurring the flow pressure loss, that on one hand, make it itself not on normal work, even not changing direction or difficult steering, on the other hand, the stability and lifetime of steering system will be reduced since the flow pressure cannot be up to the required value, (3) Said too long and complex passage may causes the oil temperature rising too fast to make the entire system of high temperature (oil temperature of engineering or mining vehicles for example, can reach from 100° C. to 160° C.), thereby aggravating the seals aging speed to easily lead to leakage. Meanwhile, high oil temperature may also leads to the oil viscosity decreasing quickly, wearing internal components of steering system out, so that resulting in the service life of the steering system greatly reduced. (4) The oil liquid of steering system can never completely eliminate the interfusion of impurity. The valve seat in pump body assembly of traditional steering pump substantially is in two configurations that a configuration with non strainer screen where impurities 22 block in the conical valve seal 23 causing untight sealing and causing the pressure never built up, even not changing direction or difficult steering, and another configuration with strainer where single-layer strainer 23 with deep structure can easily lead to impurities stacking on said strainer, even make the steering pump body explosion since the strainer is completely blocked under high pressure, as illustrated all in FIG. 3. (5) As shown in FIG. 4, the traditional processing of interior oil return passage within the pump body is generally achieved by drilling in direction perpendicular to the valve bore in which the drilled bore is in a circular shape. The small opening of the shape leading to overflow rate high is easy to cause the temperature rising very fast at overflow rate, even at high temperature, wearing the internal components of steering pump out and decreasing their lifetime.

SUMMARY

The present invention imposes to resolve the aforementioned technical problems of the prior art, further provides a power steering pump for decreasing the temperature from heat source, thereby reducing the oil temperature of vehicle steering system and improving the service life thereof.

In order to resolve the technical problem, the invention adopts the following technical solution that a power steering pump, comprising a pump body within which an inner cavity being formed, wherein a rear oil distributing plate, a blade assembly consisting of stators, rotors and blades, front oil distributing plate, and pressing springs being sequentially disposed within said inner cavity from its rear portion to front portion, a pump shaft being mounted into said inner cavity of the pump body after connecting the rear oil distributing plate, the blade assembly and the front oil distributing plate in series into one together which front end projects outwards from the front portion of the pump body and further mates with a drive gear, and which rear end is supported into the rear oil distributing plate, which is characterized in that the front oil distributing plate is enclosed with front wall of the inner cavity of the pump body to form a front outlet cavity, a valve bore being formed at outer circumference side of the inner cavity of the pump body communicates with the front outlet cavity, a flow securing control valve is disposed within the valve bore, the front outlet cavity communicates with an oil outlet hole at the front portion of pump body through a high-pressure oil passage, the outer circumference portion of the blade assembly is enclosed with inner wall of the inner cavity of the pump body to form a rear cavity of the pump body, the valve bore communicates with said rear cavity of the pump body through an oil return passage, the blades driven by a pump shaft rotate to complete oil absorbing and draining process, the flow securing control valve controls the oil volume from the front outlet cavity back to the oil return passage to maintain the oil volume drained from the front outlet cavity through the oil outlet hole at a constant value.

Further, in the preferred embodiment of the present invention, wherein the front outlet cavity is positioned vertically below the oil outlet hole, the high-pressure oil passage includes a horizontal oil passage and a longitudinal oil passage vertically below the oil outlet hole, wherein the horizontal oil passage in parallel with the pump shaft which opening communicates with the front outlet cavity, the longitudinal oil passage perpendicular to the horizontal oil passage or inclined to it at an angle from 60 to 90 degree which opening communicates with the oil outlet hole.

Further, in the preferred embodiment of the present invention, wherein an opening is formed at the rear portion of the inner cavity of the pump body and enclosed by the rear oil distributing plate.

Further, in the preferred embodiment of the present invention, wherein the front portion of the pump body is a flange portion, and rolling bearings and oil seals are arranged between the flange portion and the pump shaft, wherein the oil seal is utilized with dual lips and skeleton rotating oil seal configuration.

Further, in the preferred embodiment of the present invention, wherein a sliding bearing is further arranged between the pump shaft and the rear oil distributing plate.

Further, in the preferred embodiment of the present invention, wherein the rear oil distributing plate, the blade assembly and the front oil distributing plate are connected in series through positioning pins into one together.

Further, in the preferred embodiment of the present invention, wherein a conical valve being arranged within the flow securing control valve that comprises a conical valve core and a pressure limiting spring, wherein a conical opening matched with the conical valve core is arranged within a valve seat, the pressure limiting spring compresses the conical valve core to push it against the conical opening.

Further, in the preferred embodiment of the present invention, wherein the valve seat in the flow securing control valve is utilized with dual-layer strainer configuration, outer-layer strainer of said dual-layer strainer has 60 mesh with diameter φ0.18, inner-layer strainer of said dual-layer strainer has 120 mesh with diameter φ0.06, wherein both strainers are outward bulge configuration.

Further, in the preferred embodiment of the present invention, wherein the oil return passage is obliquely drilled in direction of the valve bore, wherein opening of the oil return passage within the valve bore represents an ellipse shape.

Further, in the preferred embodiment of the present invention, wherein 0-shape sealing rings are disposed between the outer circumference of the front oil distributing plate and inner cavity wall of the pump body, and between the rear oil distributing plate and inner cavity wall of the pump body respectively, and an 0-shape sealing ring is disposed on the surface of the flange portion of the pump body.

The advantage of the present invention states in that it adopts a high-pressure front cavity configuration of the pump body to shorten the length of high-pressure oil passage and make the passage's smooth transition, further reduce the flow pressure loss, which hence avoids steering pump failure caused by aggressive overheating generated in the traditional configuration with excessive length of the flow passage and bending. Because of inner flow passage of the pump body designed in high-pressure front cavity configuration, few processing procedures, easy process, and lower cost are achieved. Meanwhile, the integrated assembly design of rear cover with rear oil distributing plate not only reduces the manufacturing cost in aspect of the material and the processing, but also improves the stability and lifetime of assembly in view of its simplified structure. The valve seat of the invention adopts a dual-layer strainer configuration that possesses excellent straining effect and prevents being blocked resulting in explosion of the pump body. Oil return passage of the invention being obliquely drilled in direction of the valve bore within which the oil return passage represents an ellipse shape and its enough length of the opening promotes higher efficiency while effusion at low flow speed, less heat and pressure loss. The pump of the invention decreasing the temperature from heat source not only can improve the service life of the pump itself, but also the vehicle steering system.

The above described features and advantages, as well as others, will become more readily apparent to the skilled in the art by reference to the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cutaway view illustrating the traditional configuration of a steering pump assembly in prior art;

FIG. 2 is a schematic cutaway view illustrating the traditional configuration of an inner high-pressure oil passage within pump body of the power steering pump in prior art;

FIG. 3 is a schematic diagram illustrating the traditional configuration of a valve assembly of the steering pump in prior art;

FIG. 4 is a schematic diagram illustrating the position of the traditional configuration of valve assembly of the steering pump within the valve bore in prior art;

FIG. 5 is a schematic cutaway view illustrating the power steering pump assembly with front high-pressure cooling cavity of the present invention;

FIG. 6 is a schematic cutaway view illustrating high-pressure oil passage within the pump body of the power steering pump assembly with front high-pressure cooling cavity of the present invention;

FIG. 7 is a schematic diagram illustrating the configuration of a valve seat in the valve assembly of the power steering pump of the present invention;

FIG. 8 is a schematic diagram illustrating the position of the valve assembly of the power steering pump within the valve bore of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 5, a preferred embodiment of the power steering pump with front high-pressure cooling cavity of the present invention comprising a pump body 3 within which an inner cavity being formed, wherein a rear oil distributing plate 10, a blade assembly consisting of stators 12, rotors 13 and blades 14, front oil distributing plate 15, and pressing springs 16 being sequentially disposed within said inner cavity from its rear portion to front portion. A pump shaft 17 being mounted into said inner cavity of the pump body 3 after connecting the rear oil distributing plate 10, the blade assembly and the front oil distributing plate 15 in series into one together which front end projects outwards from the front portion of the pump body 3 and further mates with a drive gear 1, and which rear end is supported into the rear oil distributing plate 10, the front oil distributing plate 15 is enclosed with front wall of the inner cavity of the pump body 3 to form a front outlet cavity A, a valve bore being formed at outer circumference side of the inner cavity of the pump body 3 communicates with the front outlet cavity A, a flow securing control valve is disposed within the valve bore, the front outlet cavity A communicates with an oil outlet hole 20 at the front portion of pump body 3 through a high-pressure oil passage 21, the outer circumference portion of the blade assembly is enclosed with inner wall of the inner cavity of the pump body 3 to form a rear cavity of the pump body 3, the valve bore communicates with said rear cavity of the pump body 3 through an oil return passage B, the blades driven by a pump shaft 17 rotate to complete oil absorbing and draining process, the flow securing control valve controls the oil volume from the front outlet cavity A back to the oil return passage to maintain the oil volume drained from the front outlet cavity A through the oil outlet hole 20 at a constant value. The front outlet cavity A is positioned vertically below the oil outlet hole, the high-pressure oil passage includes a horizontal oil passage and a longitudinal oil passage vertically below the oil outlet hole, wherein the horizontal oil passage in parallel with the pump shaft 17 which opening communicates with the front outlet cavity A, the longitudinal oil passage perpendicular to the horizontal oil passage or inclined to it at an angle from 60 to 90 degree which opening communicates with the oil outlet hole. An opening is formed at the rear portion of the inner cavity of the pump body 3 and enclosed by the rear oil distributing plate 10. The front portion of the pump body 3 is a flange portion, and rolling bearings 2 and oil seals 18 are arranged between the flange portion and the pump shaft 17, wherein the oil seal 18 is utilized with dual lips and skeleton rotating oil seal configuration. A sliding bearing 9 is further arranged between the pump shaft 17 and the rear oil distributing plate 10. The rear oil distributing plate 10, the blade assembly and the front oil distributing plate 15 are connected in series through positioning pins into one together. A conical valve being arranged within the flow securing control valve that comprises a conical valve core 6 and a pressure limiting spring 5, wherein a conical opening matched with the conical valve core 6 is arranged within a valve seat 8, the pressure limiting spring 5 compresses the conical valve core 6 to push it against the conical opening. The valve seat 8 in the flow securing control valve is utilized with dual-layer strainer configuration, outer-layer strainer of said dual-layer strainer has 60 mesh with diameter φ0.18, inner-layer strainer of said dual-layer strainer has 120 mesh with diameter φ0.06, wherein both strainers are outward bulge configuration. The oil return passage B is obliquely drilled in direction of the valve bore, wherein opening of the oil return passage B within the valve bore represents an ellipse shape. 0-shape sealing rings are disposed between the outer circumference of the front oil distributing plate 15 and inner cavity wall of the pump body 3, and between the rear oil distributing plate 10 and inner cavity wall of the pump body 3 respectively, and an 0-shape sealing ring is disposed on the surface of the flange portion of the pump body 3.

The working principle of the front high-pressure cooling cavity of the power steering pump of the invention is that in two enclosure chambers enclosed by the stators 12, rotors 13, blades 14, front oil distributing plate 15 and rear oil distributing plate 10 as blades 14 are glued to the inner surface of the stator 12 under the action of centrifugal force when the steering pump driven by the engine being on work, their working volume changes from being small to being large, and then from being large to being small, compressing oil to complete an absorbing and draining oil process. The oil volume drained from the pump increases along with increasing rotate speed of rotor 13, each enclosure chamber completes twice oil absorbing and draining processes as the pump shaft 17 rotates each cycle. The drained oil is controlled through a flow securing control valve 4 and a throttle so that maintains the oil volume drained from oil outlet hole at a substantially constant value. The flow rate proceeding to increase with the increasing rotate speed promotes differential pressure of the oil drained through the throttle also increased, pushing the flow securing control valve 4 toward right, chamber A (front outlet cavity) is communicated with chamber B (the oil return passage) to form overflow therebetween so that controls excess oil flow back into the oil inlet hole. The larger volume of the oil overflow is, the bigger volume of the opening is, maintaining the oil volume drained from the pump at a substantially constant value. Conversely, The flow rate proceeding to decrease with the decreasing rotate speed promotes differential pressure of the oil drained through the throttle also decreased, pushing the flow securing control valve 4 toward left. The overflow volume being decreased maintains the oil volume drained from the pump at a substantially constant value. The oil overflow flows back into the oil inlet hole of the pump, and then participates in the next cycle. When the rotate speed is lower than the starting rotate speed of flow securing control valve 4, the flow volume will be lower than the substantially constant value thereby the volume of oil overflow is zero. When the system working pressure exceeds the pressure of flow securing control valve, a conical valve core 6 moves to left, allowing for the high pressure chamber jointing with the chamber B, then all hydraulic oil flowing back into the oil absorbing chamber, which thus achieves security protection of the system.

As shown in FIG. 6, the pump body 3 is utilized in a front high-pressure cavity configuration, wherein the high-pressure oil passage 21 is nearby the oil outlet channel 20, allowing for with simple and widen passage, low corner bending, further smoothly high-pressure oil flowing, reducing the pressure loss of flow, as well as promoting the steering pump on work in normal parameters, and improving the stability of the system. Meanwhile, and the quantities of holes required for processing, with simplified processing method, shortened processing period, and less manufacturing equipments, cutting and measuring tools, of the high-pressure flow passage within the pump body 3 is less than the conventional pump body in prior art, which hence can reduce the production cost and suitable for batch production.

As shown in FIG. 7, the valve seat 8 in the valve assembly is utilized in dual-layer strainer configuration, wherein the outer-layer strainer of said dual-layer strainer has 60 mesh with diameter φ0.18, inner-layer strainer of said dual-layer strainer with more dense screens has 120 mesh with diameter φ0.06. Both strainers are outward arc bulge configuration with preferred filtering effect. Under the high-pressure oil impact, impurities 22 cannot rest on the top portion of said arc configuration, thereby avoiding blocking the pump, or clogging in the conical valve of the valve body caused by the impurities entering therein, even not changing direction or difficult steering, and aggravating the aging of the steering pump.

As shown in FIG. 8, the oil return passage within the pump body is drilled incline to the direction of the valve bore 27 (the direction indicated as the arrow delineated in the diagram), wherein opening of the oil return passage within the valve bore represents an ellipse shape 26. While a vehicle in slow running, the high-pressure oil pushes the valve to move for a short displacement, in the same conditions, the exposed area 25 is larger than the circular hole to achieve higher efficiency of overflow and is difficult to cause excessive overheating or pressure loss problem.

According to market research, out of operation of the power steering pump caused by the oil quality problem has a big proportion about 70%˜80% in the pump failure, wherein the system overheating problem is the primary cause of the deterioration of oil used in steering system. The steering pump with front high-pressure cooling cavity embodied in the present invention is to be studied from the heating source to change the conventional configuration in prior art. It is proved that, under the same conditions, the oil temperature of steering system applied in the invention is lower about 20˜30° C. than conventional steering pump from experiments. The reduction of oil temperature can greatly improve the entire service life of power steering system.

The performance parameters of the power steering pump with front high-pressure cooling cavity of the present invention are:

1. Displacement of stator: 20 ml/r 2. Pressure ranges: max at 14.7 MPa 3. Rotate speed range: 400˜4000 r/min

Although various embodiments been presented therein, it should be appreciated by those skilled in the art that other implementation or adaptation are possible. Moreover, there are advantages to individual advancements described herein that may be obtained without incorporating other aspects described above. Therefore, the spirit and scope of the appended claims should not be limited within the description of the preferred embodiments contained herein. 

1. A power steering pump, comprising a pump body (3) within which an inner cavity being formed, wherein a rear oil distributing plate (10), a blade assembly consisting of stators (12), rotors (13) and blades (14), front oil distributing plate (15), and pressing springs (16) being sequentially disposed within said inner cavity from its rear portion to front portion, a pump shaft (17) being mounted into said inner cavity of the pump body (3) after connecting the rear oil distributing plate (10), the blade assembly and the front oil distributing plate (15) in series into one together which front end projects outwards from the front portion of the pump body (3) and further mates with a drive gear (1), and which rear end is supported into the rear oil distributing plate (10), which is characterized in that the front oil distributing plate (15) is enclosed with front wall of the inner cavity of the pump body (3) to form a front outlet cavity (A), a valve bore being formed at outer circumference side of the inner cavity of the pump body (3) communicates with the front outlet cavity (A), a flow securing control valve is disposed within the valve bore, the front outlet cavity (A) communicates with an oil outlet hole (20) at the front portion of pump body (3) through a high-pressure oil passage (21), the outer circumference portion of the blade assembly is enclosed with inner wall of the inner cavity of the pump body (3) to form a rear cavity of the pump body (3), the valve bore communicates with said rear cavity of the pump body (3) through an oil return passage (B), the blades driven by a pump shaft (17) rotate to complete oil absorbing and draining process, the flow securing control valve controls the oil volume from the front outlet cavity (A) back to the oil return passage to maintain the oil volume drained from the front outlet cavity (A) through the oil outlet hole (20) at a constant value.
 2. A power steering pump of claim 1, wherein the front outlet cavity (A) is positioned vertically below the oil outlet hole, the high-pressure oil passage includes a horizontal oil passage and a longitudinal oil passage vertically below the oil outlet hole, wherein the horizontal oil passage in parallel with the pump shaft (17) which opening communicates with the front outlet cavity (A), the longitudinal oil passage perpendicular to the horizontal oil passage or inclined to it at an angle from 60 to 90 degree which opening communicates with the oil outlet hole.
 3. A power steering pump of claim 1, wherein an opening is formed at the rear portion of the inner cavity of the pump body (3) and enclosed by the rear oil distributing plate (10).
 4. A power steering pump in claim 1, wherein the front portion of the pump body (3) is a flange portion, and rolling bearings (2) and oil seals (18) are arranged between the flange portion and the pump shaft (17), wherein the oil seal (18) is utilized with dual lips and skeleton rotating oil seal configuration.
 5. A power steering pump of claim 1, wherein a sliding bearing (9) is further arranged between the pump shaft (17) and the rear oil distributing plate (10).
 6. A power steering pump in claim 1, wherein the rear oil distributing plate (10), the blade assembly and the front oil distributing plate (15) are connected in series through positioning pins into one together.
 7. A power steering pump of claim 1, wherein a conical valve being arranged within the flow securing control valve that comprises a conical valve core (6) and a pressure limiting spring (5), wherein a conical opening matched with the conical valve core (6) is arranged within a valve seat (8), the pressure limiting spring (5) compresses the conical valve core (6) to push it against the conical opening.
 8. A power steering pump of claim 7, wherein the valve seat (8) in the flow securing control valve is utilized with dual-layer strainer configuration, outer-layer strainer of said dual-layer strainer has 60 mesh with diameter Φ0.18, inner-layer strainer of said dual-layer strainer has 120 mesh with diameter Φ0.06, wherein both strainers are outward arc bulge configuration.
 9. A power steering pump in claim 8, wherein the oil return passage (B) is obliquely drilled in direction of the valve bore, wherein opening of the oil return passage (B) within the valve bore represents an ellipse shape.
 10. A power steering pump of claim 9, wherein, O-shape sealing rings are disposed between the outer circumference of the front oil distributing plate (15) and inner cavity wall of the pump body (3), and between the rear oil distributing plate (10) and inner cavity wall of the pump body (3) respectively, and an O-shape sealing ring is disposed on the surface of the flange portion of the pump body (3). 